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John, I understand your opinion about "auto setup" from receivers, but have you actualy used Audyssey? I agree with you on past versions, but I have really read a lot of good reviews and feedback that this truely is a different animal from previous products.

Audyssey company actually says that it is not a replacement for room treatments, but when combined gives you unbelievable results.



Hi Randy

My knock is not at Audessey a much as the claims made by AVR manufacturers regarding the benefits of auto-equalization. The complex physics involved pretty well rule out a silver bullet approach but it makes for great marketing.

In room acoustical problems can be categorized into frequency domain and time domain issues. To date most equalizers deal in the frequency domain and not time domain which is why I always urge that equalization be used sparingly and only after all other solutions. Auto-equalization in particular is an imperfect approach to an almost insoluble task.

Fixing combined time domain/FR problems with electronic correction is a tricky proposition. I have never heard one which actually set auto-equalization/delay correctly for subwoofers let alone other speakers. The physics involved make it very difficult for an automated program with limited processing power to do well. Its actually refreshing to buy equalizers (DEQ2496) with auto-programs where the manufactuer(Behringer) specifically warns not to use such programs for frequencies less than 100hz and that better reusults can be obtained with custom settings . To date those issues are best dealt with judicious use of manual equalization, room treatments, bass traps and processor delay. Even my SMS-1 performs best with manual tweaking. The auto-results with SMS-1 and all auto-programs create as many problems as they solve by attempting to boost nulls or cut output at the wrong frequencies. And by doing so make the time domain ringing problems worse by adding excessive equalization.

What Audessey or any auto program is trying to do involves Sweep,Measure, Adjust, Sweep, Measure, Adjust.. a long iterative process involving continuous incremental adjustments in the frequency domain. Anyone who has used sweeps and an equalizer goes through it, the main difference is you are now having to consider more measuremnts at more locations. I've spend several idle afternoons optimizing response across six seats this way using the SMS_1 display and delay on the processor . I very much doubt an auto program could optimize the huge tradeoffs involved as well without a huge dedicated processor. Maybe one day with more powerful chips but not with the current technology inside receivers, which is why I am quite cynical about the claims.

In any of my friends setups which I have looked at the low frequency settings were never right. And after listening to the obvious ringing throughout the room caused by adding too much equalization, I've often suggested my friend's shut off the auto-equalization and get a good cheap simple manual equalizer and just tame the sweet spot.

There are advances on the horizon which do look promising however, by Audessey in fact. They have a new equalizer AS-EQ1 which purportedly deals with equalizing delay times and frequency response simultaneouly using fuzzy logic algorythms. It can be attached to a PC or notebook for the processing pwer needed to do complex iterative calculations, a key tool which is missing in the Denons or Yamahas.

Invariably for now, you will get better results with a simple equalizer when you take the time to manually configure it yourself at the sweet spot...and use sparingly.

John